- - - Assistant Professor, Tehran University, Tehran, Iran
- - - Ph.D. student, Tehran University, Tehran, Iran

Recent research suggests that critical thinking is not typically an intrinsic part of instruction at any level. Students come without any training in it, while faculties tend to take it for granted as an automatic by-product of their teaching. Yet without critical thinking systematically designed into instruction, learning is transitory and superficial. Therefore, the purpose of the present study is to investigate the impacts of teaching critical thinking skills on the development of the reading and writing abilities of Iranian EFL learners, in line with other studies confirming the positive relationship between critical thinking and language skills. The treatment consisted of ۱۸ instructional sessions of ۲۰ minutes on critical thinking. The participants of the study were ۵۰ male and female students with pre-advanced proficiency level. The students in the experimental group were taught critical thinking skills beside other materials while the students in the control group did not have critical thinking instruction. The data were analyzed using several independent t-tests which were administered across pre-test and post-test scores. The results indicated that critical thinking led to students' significant improvement in reading and writing abilities in the experimental group. The results have implications for teachers, institutes and material designers.

Critical Thinking, English as a Foreign Language (EFL), Problem-solving tasks, Reading ability, Writing ability